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Expanded DNA Testing for Breast Cancer

Researchers were able to pinpoint specific therapies for some women in study

WebMD News Archive

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"It is very expensive, very labor intensive," he said. "In the United States, the approach is evolving."

The cost of whole-genome testing varies greatly, but some laboratories offer it for less than $10,000. Experts say the cost will drop more in the future.

Dr. Claudine Isaacs, a professor of oncology at the Georgetown Lombardi Comprehensive Cancer Center, in Washington, D.C., said the approach has advantages.

"The advantage of screening the tumor either for a large battery of mutations or doing whole-genome analysis is that it gives a much broader analysis and understanding of possible patient- or tumor-specific molecular 'drivers' for that particular tumor," said Isaacs, who also reviewed the findings. "It will pick up both suspected and unsuspected [genetic] alterations."

"I do think this is the wave of the future," she said. "The hope of such an approach is to better provide our patients with a personalized approach to their care."

As promising as the approach is, Somlo said, it's important to realize that "not every tumor needs to have whole-genome testing." It's already known that some specific mutations or changes in genetic activity will result in particular breast cancer patients benefiting from targeted therapy, he said.

For instance, he said, the drug trastuzumab (Herceptin) is used as a targeted therapy for women found to be over-activating the protein known as HER2 (human epidermal growth factor receptor).

For breast cancer patients, the difficulty of finding an effective treatment increases when the disease spreads, Somlo said.

"There are multiple mutations and the curability of those patients is very low," he said. Obtaining the genetic information in these cases would best be done as soon as possible after the cancer's spread is detected, he said.